Bacterial metabolites with communicative functions could provide protection against stress conditions to members of the same species. Yet, information remains limited about protection provided by metabolites in Bacillus cereus and inter-species. This study investigated the effect of extracellular compounds derived from heat shocked (HS) and non-HS cultures of B. cereus and Geobacillus stearothermophilus on the thermotolerance of non-HS vegetative and sporulating B. cereus. Cultures of B. cereus and G. stearothermophilus were subjected to HS (42 or 65 °C respectively for 30 min) or non-HS treatments. Cells and supernatants were separated, mixed in a combined array, and then exposed to 50 °C for 60 min and viable cells determined. For spores, D values (85 and 95 °C) were evaluated after 120 h. In most cases, supernatants from HS B. cereus cultures added to non-HS B. cereus cells caused their thermotolerance to increase (D 50 12.2-51.9) when compared to supernatants from non-HS cultures (D 50 7.4-21.7). While the addition of supernatants from HS and non-HS G. stearothermophilus cultures caused the thermotolerance of non-HS cells from B. cereus to decrease initially (D 50 3.7-7.1), a subsequent increase was detected in most cases (D 50 18-97.7). In most cases, supernatants from sporulating G. stearothermophilus added to sporulating cells of B. cereus caused the thermotolerance of B. cereus 4810 spores to decline, whereas that of B. cereus 14579 increased. This study clearly shows that metabolites in supernatants from either the same or different species (such as G. stearothermophilus) influence the thermotolerance of B. cereus.

• MeSH
• Bacillus cereus účinky léků   metabolismus   fyziologie   účinky záření   MeSH
• Geobacillus stearothermophilus metabolismus   fyziologie   účinky záření   MeSH
• mikrobiální interakce * MeSH
• mikrobiální viabilita účinky léků   účinky záření   MeSH
• spory bakteriální účinky léků   fyziologie   účinky záření   MeSH
• teplota MeSH
• termotolerance účinky léků   MeSH
• vysoká teplota MeSH
• Publikační typ
• časopisecké články MeSH

Two thermophilic strains belonging to Geobacillus stearothermophilus and Meiothermus ruber, which naturally do not synthesize ω-alicyclic fatty acids (ω-FAs) were cultivated with cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl carboxylic acids. Gas chromatography-mass spectrometry analysis of fatty acid methyl and picolinyl esters showed that both strains are able to synthesize ω-FAs when cultivated with the appropriate precursor. The incorporation of cyclic acids influenced the whole FA composition as well as membrane fluidity. Membrane fluidity of intact cells was studied by measuring the fluorescence polarisation of the probe l,6-diphenyl-1,3,5-hexatriene incorporated into membrane lipid bilayers. Cytoplasmic membrane became more fluid with increasing content of ω-FAs. This is caused by considerable changes in lipid packing within the membrane induced by the presence of ω-FAs not found in the natural environment of Geobacillus and Meiothermus strains.

• MeSH
• buněčná membrána metabolismus   MeSH
• difenylhexatrien metabolismus   MeSH
• fluidita membrány MeSH
• fluorescenční barviva metabolismus   MeSH
• fluorescenční polarizace MeSH
• Geobacillus stearothermophilus metabolismus   MeSH
• gramnegativní bakterie klasifikace   metabolismus   MeSH
• kyseliny karboxylové metabolismus   MeSH
• nenasycené mastné kyseliny biosyntéza   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH